Fuel control valves



March 1961 G. H. GARRAWAY ET AL 76,885

FUEL CONTROL VALVES 2 Sheets-Sheet 1 Filed July 8, 1955 INVENTORS GEORGEH. GARRAwAY HT 5 A RICHARD F? KumuP, I

BY M y/w ATTORNEYS G. H. GARRAWAY ETAL 2,976,885

March 28, 1961 FUEL CONTROL VALVES 2 Sheets-Sheet 2 Filed July 8, 1955 Sm H m: w W? n Q g BY M7/% #0 FUEL CONTROL VALVES George H. Garraway,Darien, Conn, and Richard P.

Kirkup, Packanack Lake, N.J., assignors to Orr & Sembower, Inc.,Reading, Pa., a corporation of Pennsylvania Filed July 8, 1955, Ser. No.520,694

2 Claims. (Cl. 137-608) This invention relates to flow control valvesfor fiuid circulation systems and the like, and more particularly toimprovements in pressure sensitive flow control valves for use in fuelsupply systems.

This application is a continuation-in-part of the copending applicationof George H. Garraway and Richard P. Kirkup Serial No. 213,068, filedFebruary 28, 1951, which issued on July 10, 1956, as Patent No.2,753,927.

In the past it has been customary to supply liquid fuel, such as oil, toan atomizing fuel injector assembly from a fuel pump either directly orthrough an oil pre-heater, the flow of fuel to the injector assemblybeing controlled by a pressure regulating valve. Such pressureregulating valves are usually provided with a return outlet con nectedto permit recirculation of fuel to the fuel supply source, the amount offuel flowing in the return line being usually determined by the inputpressure acting on'the pressure regulating valve. One example of suchprior art systems is that disclosed in United States Letters Patent No.2,000,733 for Burner Installation'f or Domestic Boilers, issued to E. G.Avery.

For optimum efliciency of operation, it is desirable to supply fuel tothe atomizing' nozzle at constant rate, either at constant pressure orat constant weight or volume of fuel per unit of time. In prior systemscontrolled by conventional pressure regulating valves, changes inviscosity of the oil resulting from the natural swing or hunt of the oiltemperature control mechanism controlling the oil pre-heater, and thevariation of oil analysis from one delivery to the next, prevent themaintenance of a constant firing rate. Also in such prior systems,variation of pressure on the discharge or nozzle side of the pressureregulating valve resulting from variations in pipe friction between thevalve and the nozzle, changes in fuel viscosity, collection of carbon ordirt particles in the oil ports of 'the nozzle, and minute differencesin size of the oil ports in nozzles of nominally identical size changedin the field, as well as changes in the air pressure supplied for fuelatomization resulting from carbon or dirt particles in the air flowpassages in-the nozzle, fading of the compressor, replacementof thecompressor, or minute differences in size of the air flow passages innominally identical nozzlesj all produce undesirable variations in thefuel firing rate. The fuel firing rate will also vary in such prior artsystems with different grades of fuel oil used. a

It is, accordingly, a primary object of this invention to overcome theseand other disadvantages 'of prior fuel regulating systems by providingnew and improved ,fuel flow control valves adapted to maintainpredetermined fuel flow characteristics over a wide range of operatingconditions.

A further important .object'of .thisjl'nvention is theprov vision of newand improved fuel controlv valves including differential pressuresensitivevalve actuating means subjected at one side to-fuel supply spressure and at the other side to a control pressurejsuch 1as]tonaintain2,976,885, Patented Mar. 28, 1961 2 predetermined desired fuel flowcharacteristics over wide ranges of variation of operating conditions.

Another object of the invention is the provision of a novel fuel controlvalve including means defining a main fuel flow passage having avariable area orifice therein adjustableto desired fuel flowsettings-and a fuel by-pass passage having a valve therein actuated bydifferential pressure responsive means to maintain substantiallyconstant fuel flow at each setting by controlled by-pass of fuel throughthe by-pass passage.

Still another object is the provision of such valves wherein thedifferential pressure responsive means is subjected at one side to fuelpressure upstream of the variable area orifice and at the other side toatmosphere, so as to maintain substantially constant fuel pressure inthe main fuel passage upstream of the orifice.

Yet another object of the invention is the provision of new and improvedfuel control valves including means defining a variable area orificewhich remains substantially of the same shape for all area settings tothus minimize the effects of fuel viscosity variation and fluidfriction.

' A further important object of this invention is to provide a fuelcontrol valve of the character mentioned with a differential pressureresponsive means having a connection on the control side thereof adaptedeither to flush out the burner supplyline or to return leakage fluid toa fluid return line leading to the fuel supply reservoir.

Still another object of thisinvention is to provide a fuel control valveof the character mentioned with a piston type differential pressureresponsive means capable of efficient long life operation. i V

Also an object of the invention is the provision of novel fuel flowcontrol valves characterized by simplicity of structure, economy ofmanufacture and long trouble-free service life.

These and other objects, features and advantages of the invention willbecome apparent as the description proceeds in connection withtheappendedclaims and accompanying drawings wherein like reference numeralshave been used to designate like parts and wherein:

Figure 1 is a diagrammatic view of a fuel circulating systemincorporating improved fuel control valves embodying the invention; i

Figure 2 isa partially sectional view of one of the valves of thecirculating system of Figure 1 connected to function as a constantpressure valve;

Figure 2A is a fragmentary sectional view illustrating the differentialpressure responsive means of Figure 2 in fuel by-passing position;

Figure 3 is a sectional view of an adaptation of the fuel control valveof Figure Zillustrating a preferred pressure responsive 1, oil issupplied to this system from an inlet conduit 10- through an oilstrainer 12 to an oil pump 14. Oil pump 1 14"f01ces oil through an oilpreheater 16 and thence through conduit 17 to a constant pressurevalveflS made in accord with this invention. Valve 18 is provided withan inlet connection 20, an outlet connection 22 to the burner, and areturn outlet connection zd for oil rec'irculation. .A return conduitf26is connected between outlet 24 and conduit 10. An oil recirculatingvalve27 is shown mounted as ansend adapter oftheoil injector assembly '28 andis provided with a fuelinlet 29 .con-

nected by conduit 30 to outletlzz of the constant pressure valve 18, afuel conducting tube 31 leading directly to the nozzle 32 of the fuelinjector assembly 28, and a fuel return outlet 33 suitably connectedthrough conduit 34 to the fuel return line 26.

Recirculating valve 27 and the associated burner structure may be of thetype disclosed in our aforesaid copending application S.N. 213,068, andis operable to direct fuel flow entering through its inlet connection 29either to the fuel tube 31 of burner nozzle 32 or to the fuel returnoutlet 33 for recirculation through the fuel supply system duringperiods of inoperation of the burner.

The temperature of the oil supplied to the constant pressure valve 18through inlet 29 is controlled at the oil preheater 16 which may be aheat exchanger unit of generally conventional design. In the preheaterhere disclosed, steam is supplied from an inlet 35 through a valve 36actuated by a regulator 38. Steam condensate is removed from the oilpreheater 16 through pipe 39, steam trap 42, and pipe 44. Regulator 38is connected through cable 46 to a thermal responsive element Withincoupling 48 in line 17 so that the supply oil temperature controls thedegree of oil preheat. Due to the lag in this control, the supply oiltemperature will fluctuate about an established operating norm.

The structural details of one form of constant pressure valve 18 areillustrated in Figure 2. The body 50 of this constant pressure valve 18is formed with two chambers 52 and 54 interconnected by a series oflongitudinal passages 56. Oil inlet connection 20 opens directly intochamber 52. Two outlet chambers 58 and 60 are formed within the bodystructure 50 intermediate the chambers 52 and 54. A bore 59 connectschambers 52 and 60, and a bore 61 connects chambers 54 and 58. A valvestem 62, having at least one longitudinally extending groove 63 ofchanging size formed on its outer surface, is mounted for axial slidingmovement in bore 59. Valve stem 62 is shown in Figure 2 in its closedposition, that is with groove 63 out of communication with inlet chamber52 and a stop ring portion 65 abutting against the body as shown. Asvalve stem 62 is moved down through bore 59, groove 63 forms anintercommunicating channel between chambers 52 and 60 to permit passageof oil from inlet 20 to outlet 22 and the burner. Since the size ofgroove 63'varies along its length, the quantity of oil flow can beaccurately controlled by the longitudinal position of valve stem 62.Valve stem 62 extends below the valve assembly 18 and is connected to aclevis 66. Leakage of oil along the valve stem 62 is prevented by asubstantially conventional stufiing box assembly 68 including spring 79and packing material 72. The position of valve stem 62 may be variedeither manually or by any suitable conventional automatic controllingmechanism for controlling the quantity of fuel flow through outletconnection 22 to the fuel injector assembly 28.

A valve member '76 has a neck 77 and a conical tip 77 adapted to bedisposed in bore 61 and actuated in response to oil pressure at theinlet 20. Its purpose is to control recirculation of oil in the system.Oil from chamber 52 passes through passages 56 into chamber Valve member76 is fixed to the movable end of a pressure control bellows 7 8 and maybe adjustably preloaded by a spring 89 therein. The preloadingadjustment of the valve 76 is controlled by manipulation of screw 32 tovary the initial compression of spring sththisscrew being provided witha lock nut 34 to hold the adjustment. The interior of bellows 78 in thisuse of the valve is open to atmosphere through a port or other opening79 through the top closure plate 86 of valve body 5%.

In operation. the constant pressure valve 18 is effective to vary therate of flow through the return outlet connection 24 to maintain the oilinlet pressure within chainber 52 substantially constant regardless ofthe selected or set position of the valve stem 62. When oil circulationl starts the oil pressure built up in chamber 54 4 eventuallyovercomes the resistance of bellows 78 and spring to raise valve neck 77out of bore 61 (see Fig- -ure 2A) and permit flow of oil through bore59, chamber 58 and outlet return connection 24. A stable condition issoon reached for a given pump pressure corresponding to desired oilpressure in chamber 52 which results in a certain throttling position ofconical tip 77 in bore 61.

Suppose the oil pressure in chamber 52 increases and undesirably tendsto increase the fiow of oil through burner outlet 22. The pressureincrease is transmitted through passages 56 to chamber 54 to furthercollapse bellows 78 and further open bore 61 to increase the flow of oilinto chamber 58, thereby effectively reducing the oil pressure inchambers 54 and 52 until the desired oil feed pressure is restored inchamber 52. The same but opposite action takes place when the oilpressure in chamber 52 becomes reduced.

Figure 3 illustrates a preferred form of constant pressure valve whichdiffers from that just described principally in its use of a piston typepressure responsive element in preference to the bellows or Sylphonelement of Figure 2.

Constant pressure valve 90 of Figure 3 comprises a valve body or casing92 formed with two inlet chambers 94 and 95 interconnected by a seriesof longitudinal passages 97, and with two outlet chambers 99 and 100.Fuel flow to outlet chamber 99 from inlet chamber 94 is controlled by avalve stem 102 which is slidable in a bore 194 in the valve body and isprovided with one or more longitudinal grooves 106 of tapering width asshown. Valve stem 102 extends to the exterior of the valve casing andmay be provided at its outer end with suitable means such as the biasingspring 108, cam follower head 109 and bearing means 110 shown, forcoaction with suitable manual or automatic control mechanism (not shown)which may be of conventional type.

The pressure responsive by-pass valve assembly 112 in Figure 3 includesa valve member 114 having a neck portion 116 and conical tip portion 117adapted to engage in a bore 119, interconnecting inlet chamber 95 andout let chamber 100. Valve member 114, through its tip 117, controlsfuel flow between these chambers. The control obtained is responsive tothe pressure difference across valve member 114 which constitutes a.piston type differential pressure sensitive element slidable in bore 121in a valve guide member 123 secured in the upper end of valve body 92.Valve member 114 is downwardly biased by a spring 125 so as to, normallyclose flow passage 119, the pre-load applied by spring 125 being readilyadjustable through an adjustment screw 127 threadedly received in a borein guide member 1237 After proper spring ad justment or re-adjustmenthas been effected, the adjustment mechanism preferably is sealed againstfluid leakage outwardly along the adjustment screw by provision of a capnut 129 threaded onto guide member 123 into engagement with a gasket asillustrated.

Since the-re may be some slight leakage of fluid about the pistonsurfaces of valve member 114, particularly if the oil ports in theburner nozzle should become clogged or if for other reasons pressure ininlet chamber 95 should become excessive, the space 139 within guidemember 123 above the piston 114 preferably is connected through outletfitting 131 to an oil return line or elsewhere as will hereinafter bedescribed with. particular reference to Figure 4.

The mode of operation of the constant pressure valve of Figure 3 issubstantially like that of Figure 2. The improved construction of theFigure 3 valve, however, affords longer and more satisfactory serviceand complete freedom from the possibility of rupture of bellows and likepressure sensing elements with consequent leakage of fuel and repaircosts.

Referring HOWtO Figure 4, a modified fuel supply systemis'shown'wherein'the fuel recirculating valve 133corresponding to valve 27 inFigure 1 is separate from the burner head assembly 135 and is ofsolenoid actuated type. The recirculating valve 133 of Figure 4functions in substantially the same manner as that of Figure 1, todirect fuel flow entering through its supply line 30 from pressureregulator 90 either through conduit 134 to the burner head 135 or to aconduit 137 connecting into fuel return line 26 for recirculationthrough the supply system.

As noted above, constant pressure valve 90 may have its outlet fitting131 from the space above piston 114 (Figure 3) connected into the fuelreturn line 26 as by a conduit 139, vent means 141 preferably beingprovided as shown in the return line to assure that pressure above thevalve piston remains atmospheric.

Suitable valve actuator means such as cam 143 and camshaft 145 may beprovided, the camshaft being rotatable either manually or automaticallyto control rate of flow through the valve responsive to the constantpressure maintained within it.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States LettersPatent is:

1. In a fuel supply system for a fluid fuel burner, a fuel flow controlvalve comprising a body structure having formed therein a first inletchamber, first and second outlet chambers and a second inlet chamberspaced in that order serially along the length thereof, a first passagemeans in said body structure interconnecting said first and second inletchambers, a second passage means in said body structure interconnectingsaid first inlet chamber and said first outlet chamber, means providinga selectively variable orifice in said second passage means, meansselectively operative independently of the pressure of the fiuid in anyof said chambers for actuating said variable orifice providing means tovary the size of the orifice in said second passage, and means formaintaining the fluid pressure at the upstream side of said variableorifice providing means in a predetermined relation to a second pressureat all settings of said variable orifice providing means, said lastnamed means comprising a third passage means in said body structureinterconnecting said second inlet and said second outlet chamber andproviding a valve passage, a valve member in said second inlet chambercooperating with said valve passage to control fuel flow to said secondoutlet chamber, and movable wall means defining at least a portion ofthe Wall of said second inlet chamber and subjected at one side to thepressure in said second inlet chamber and on the other side to saidsecond pressure and operatively connected to said valve member to modifythe proportional flow of fuel through said second and third passagemeans.

2. The fuel flow control valve defined in claim 1 wherein said movablewall means comprises a bellows element mounted in said second inletchamber with its exterior subjected to fuel pressure in that chamber andits interior open to atmosphere whereby said second pressure is atmospheric pressure so as to maintain substantially constant pressure insaid first and second inlet chambers by controlled by-pass of fuelthrough said third passage means to said second outlet chamber.

References Cited in the file of this patent UNITED STATES PATENTS862,867 Eggleston Aug. 6, 1907 1,585,732 Otto May 25, 1926 1,661,450 VanSant Mar. 6, 1928 1,899,396 Ray Feb. 28, 1933 1,980,478 Frentzel Nov.13, 1934 1,985,279 Buller Dec. 25, 1934 2,070,411 Powers Feb. 9, 19372,178,223 Czornecki ,Oct. 31, 1939 2,448,429 Henry Aug. 31, 19482,573,724 Neal Nov. 6, 1951 2,616,254 Mock Nov. 4, 1952 2,781,049Binford et al Feb. 12, 1957

